1. Field of the Invention
The present invention relates generally to apparatus and methods for providing percutaneous access to an internal operative site during a surgical procedure. More particularly, the present invention relates to a trocar system which can be percutaneously introduced while in a narrow diameter configuration and which after introduction can be radially expanded to accommodate passage of larger diameter surgical instruments.
Minimally invasive surgical procedures rely on obtaining percutaneous access to an internal surgical site using small-diameter access tubes (typically 5 to 12 mm), usually referred to as trocars, which penetrate through the skin and which open to the desired surgical site. A viewing scope is introduced through one such trocar, and the surgeon operates using instruments introduced through other appropriately placed trocars while viewing the operative site on a video monitor connected to the viewing scope. The surgeon is thus able to perform a wide variety of surgical procedures requiring only several 5 to 12 mm punctures at the surgical site. Patient trauma and recovery time are thus greatly reduced.
Particular minimally invasive surgical procedures are often referred to based on the type of scope used to view the region of the body which is the operative site. Thus, procedures in the abdominal area, which rely on a laparoscope for viewing, are referred to as laparoscopic procedures. In such laparoscopic procedures, the patient""s abdominal region is typically insufflated (filled with pressured carbon dioxide or nitrogen gas) to raise the abdominal wall and create sufficient operating space to perform a desired procedure. The trocars used in laparoscopic procedures must therefore include a valve at their proximal end to allow passage of the scope or surgical instruments while inhibiting leakage of the insufflating gas. It has also been proposed to perform laparoscopic procedures by mechanically expanding the abdomen rather than using insufflation.
Other minimally invasive surgical procedures include thoracoscopic procedures performed in the region of the chest, arthroscopic procedures performed in body joints, particularly the knee, gynecological laparoscopic procedures, and endoscopic surgical procedures performed in various regions of the body, typically with a flexible scope. These latter procedures do not normally employ pressurization and the trocars used generally do not include pressure valves at their proximal ends.
The design of suitable trocars must fulfill many requirements, particularly for those used in laparoscopic procedures in a pressurized environment. All trocars should be introducible to the patient with minimum trauma and with minimum risk of injury to internal organs. The trocars used in laparoscopic procedures should be readily sealable to inhibit the leakage of gas form the abdomen, and in particular should be designed to inhibit leakage in the region surrounding the external periphery of the trocar which passes through the abdominal wall. It is further desirable that trocars have means for anchoring within the percutaneous passage, and it would be particularly desirable if a single trocar could accommodate instruments having a wide variety of cross-sectional shapes and sizes.
Heretofore, trocar designs have met the above listed requirements with mixed results. The accommodation of various sized instruments has been met by providing trocars having different fixed diameters. Often, a surgeon will introduce the largest sized trocar, usually 10 to 12 mm, which can then accommodate most or all instruments (which are sized within this maximum) using a rubber adapter. While such an approach is feasible, the introduction of larger sized trocars exposes the patient to greater trauma and risk of injury than would be the case if smaller trocars were used.
External sealing about the periphery of the trocar has also not been adequately addressed. Certain trocar designs employ a tapered helical thread about their periphery. The thread is useful for anchoring, but greatly enlarges the trocar puncture in order to seal against the loss of pressurized insufflation gas. Other anchors, such as malecot structures have been employed on the distal end of the trocars, and are effective for anchoring but provide little sealing against the loss of pressure.
For these reasons, it would be desirable to provide trocars suitable for use in laparoscopic and other minimally invasive surgical procedures which can be easily introduced to the patient via a relatively small puncture (preferably less than 5 mm), which can then be radially expanded (and optionally subsequently reduced) to accommodate a wide variety of instrument sizes, and which provide for improved sealing about the trocar periphery and anchoring within the target site of the operative procedure.
2. Description of the Background Art
U.S. Pat. No. 5,183,464, assigned to the assignee of the present invention, describes a radially expandable dilator including an elongate dilation tube which receives an elongate expansion tube. European Patent Application 385 920 describes a variable diameter braid structure intended for capturing and removing stenotic material from blood vessels. U.S. Pat. No. 5,122,122, describes a trocar sleeve having a malecot structure at its distal end. Trocars for use in laparoscopic procedures are commercially available from suppliers such as United States Surgical Corp., Norwalk, Connecticut; Endomed division of Cooper Surgical, Inc., Shelton, Connecticut; and Dexide Inc., Fort Worth, Tex.
U.S. Pat. No. 4,738,666, describes an expandable catheter having an external sheath which is perforated to facilitate removal as the catheter is being expanded. U.S. Pat. No. 4,601,713, describes a variable diameter catheter having an inflatable retention balloon at its distal end. The catheter is introduced with an internal stylet which holds the catheter in a collapsed (reduced diameter) configuration. Removal of the stylet allows the catheter to expand. U.S. Pat. No. 4,141,364, describes an expandable endotracheal tube which is inserted in a collapsed configuration and springs back to an expanded configuration when air is introduced. Inflatable dilator apparatus are described in U.S. Pat. Nos. 4,589,868 and 2,548,602. Catheters having expandable structures are described in U.S. Pat. Nos. 4,986,830; 4,955,895; 4,896,669; 4,479,497; and 3,902,492.
U.S. Pat. No. 4,772,266, describes a dilator/sheath assembly that may be passed over an in-dwelling guide wire in order to enlarge an access hole, with entry of the sheath further enlarging the hole. U.S. Pat. No. 1,213,001, describes a trocar and cannula assembly which includes an intermediate tube to form a three-piece structure. U.S. Pat. No. 3,742,958, discloses a cannula having an axial slot to allow the cannula to be stripped from a working catheter which has been introduced through the cannula. U.S. Pat. Nos. 4,888,000; 4,865,593; 4,581,025; 3,545,443; and 1,248,492, each describe devices suitable for percutaneous penetration of a body cavity, blood vessel, or solid tissue. The disclosures of each of the U.S. Patents cited in this paragraph are hereby incorporated herein by reference.
U.S. Pat. No. 4,899,729, describes an expansible cannula which includes a coiled conical sheath which can be percutaneously introduced and thereafter expanded by advancing an internal cylinder. U.S. Pat. No. 4,716,901 discloses an expandable trocar (not including a trocar valve) comprising a pair of opposed components having sharpened distal tips and covered by an elastic sleeve over a proximal portion thereof. U.S. Pat. No. 4,846,791, describes a multi-lumen catheter which includes an elastic outer sleeve and an internal divider which, when inserted, expands the sleeve. See also U.S. Pat. Nos. 668,879; 3,789,852; 4,411,655; 4,739,762; 4,798,193; 4,921,479; 4,972,827; 5,116,318; and 5,139,511, which were made of record in U.S. Pat. No. 5,183,464, assigned to the assignee of the present invention.
A dilator assembly including a guide member having an anchor at its distal end is described in copending application Ser. Nos. 07/616,122 and 07/913,129, assigned to the assignee of the present invention, the disclosures of which are incorporated herein by reference. A peel away sheath is described in copending application Ser. No. 07/967,602, assigned to the assignee of the present invention, the disclosure of which is incorporated herein by reference.
According to the present invention, improved apparatus and methods for forming and enlarging percutaneous penetrations into target locations within a patient""s body are provided. The apparatus comprises an elongate dilation member including a radially expandable tubular braid and an elongate expansion member which is received in an axial lumen of the elongate dilation member to radially expand the braid and provide an enlarged access lumen therethrough. The elongate dilation member further includes a puncturing means near its distal end, typically being an elongate penetrating element having a sharpened distal tip which is removably received in and extends distally from the axial lumen of the braid. The elongate dilation member may thus be percutaneously introduced by puncturing the skin. The penetrating member is then removed to permit introduction of the elongate expansion member. The elongate expansion member includes a fixed-radius tubular element having an axial lumen which defines the desired access path.
The expanded braid of the elongate dilation member provides both an anchoring function and a sealing function. The tubular braid, which is preferably in the form of a mesh formed from non-elastic polymeric, stainless steel, or other filaments, shortens as it is radially expanded, causing the braid to tighten or clamp on the tissue with which it is in contact. Such tightening of the braid, when combined with the radial expansion, prevents separation of the tissue layers, provides excellent anchoring of the elongate dilation member within the percutaneous penetration, and enhances the peripheral sealing to inhibit loss of insufflation pressure utilized in laparoscopic procedures. A further advantage of the tubular braid in the elongate dilation member is that it will remain in place as the elongate expansion member is withdrawn therefrom. Thus, elongate expansion members having different cross-sectional areas and geometries can be introduced and withdrawn into the lumen of the tubular braid, thus allowing the cross-sectional area of the access lumen to be changed as desired. Tissue over the exterior of the braid will be able to stretch or relax, as appropriate, to accommodate such changes in diameter of the braid.
In a preferred aspect of the present invention, the elongate dilation member further comprises a removable protective sheath formed over the braid to facilitate the initial percutaneous introduction. After the elongate dilation member is in place, the protective sheath can be removed, either before, during, or after expansion of the tubular braid. In an exemplary embodiment, the removable sheath is axially split as the tubular braid is radially expanded, and the split portions of the sheath removed after expansion.
In a second preferred aspect of the present invention, the elongate expansion member further includes a rod having a tapered distal end removably received in the axial lumen of the fixed-radius tubular element. The tapered end extends distally from the tubular element, thus facilitating introduction of the expansion member through the axial lumen of the tubular braid. The rod can be withdrawn from the tubular element after it has been introduced through the braid, leaving the lumen of the tubular element available as the desired percutaneous access path.
In a further preferred aspect of the present invention, the elongate expansion member will include means for attaching a trocar valve at its proximal end. Typically, the trocar valve will be removably attached to the expansion member, permitting the same trocar valve to be used on different elongate expansion members having different cross-sectional areas, as they are exchanged during a procedure.
In a further preferred aspect of the present invention, the elongate penetrating element is a needle having a retractable obturator at its distal end. The obturator retracts as the needle is penetrated through skin, and extends forwardly as soon as the needle enters the patient""s body, thus helping to protect the patient against accidental injury from the needle. The exemplary needle is a Veress needle of a type commonly used in insufflation devices.
The present invention further provides an improved radially expandable dilator of the type including a radially expandable dilation member and an elongate expansion member which is insertable through an axial lumen of the dilation member. The improvement comprises an expandable dilation member including a radially expandable tubular braid covered by a removable sheath. The tubular braid preferably comprises an open mesh composed of a non-elastic polymeric or metallic filaments, whereby the braid will shorten as its radius is increased.
The present invention still further provides an improved trocar of the type having a fixed-radius tubular element and a trocar valve disposed at a proximal end of the tubular element. The improvement comprises providing a plurality of tubular elements having different fixed diameters and interchangeable means at their proximal ends for securing a trocar valve thereto. The trocar further comprises means defining a radially expandable axial lumen for selectively receiving and conforming to particular ones of said plurality of tubular elements, whereby the defining means may be percutaneously introduced to provide an access lumen for introducing and interchanging tubular members, with the trocar valve being selectively attached to the tubular element after it has been introduced. Preferably, the defining means comprises an elongate radially expandable tubular braid having means at its distal end for puncturing tissue as the braid is percutaneously advanced.
The method according to the present invention comprises penetrating an elongate dilation member through a body surface to a target location within a patient""s body. Optionally, a cover may be removed from the dilation member to expose a radially expandable tubular braid having an axial lumen which extends from the body surface to the target location. A first fixed-radius tubular element is then inserted through the lumen of the tubular braid, whereby the tubular braid is expanded to anchor itself within the percutaneous penetration. The tubular element thus provides an access lumen having an enlarged cross-sectional area. Optionally, the method further comprises removing the first fixed-radius tubular element and inserting a second fixed-radius tubular element having a lumen with a different cross-sectional area than that of the first tubular element. In this way, access lumens having a desired cross-sectional area can be introduced at the same location while causing the patient minimum trauma. Tissue abrasion is reduced or eliminated by sliding the second tubular element through the tubular braid, and there is no need to form new percutaneous penetrations.